Agents that Prevent Gene Silencing and Allow for Long Term Expression of Transgenes

Background:
The National Cancer Institute's Laboratory of Molecular Pharmacology is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize gamma-satellite DNA insulators for stable transgene expression.

Technology:
Introduction of genetic material into an organism or vector construct and proper expression of that material is critical to cellular reprogramming approaches. The lack of stable expression of these transgenes in target cell lines remains a serious problem for researchers. Once integrated into chromosomes, expression may be regulated by various position effects associated with the surrounding chromatin that are capable of inhibiting gene expression and neutralizing the intended effect of the inserted transgene.

Experimental results suggest that gene position effects can be partially overcome by flanking the transgene with regulatory elements called chromatin insulator. These insulators can overcome position effects by shielding the promoters from the influence of neighboring regulatory elements, or by preventing the spread of heterochromatin which can lead to subsequent gene silencing.

This invention discloses the use of gamma satellite DNA as highly efficient chromatin insulators that have a remarkable ability to overcome position effects and prevent the silencing of transgenes. Stable transgene expression was recorded for well over eight months when human chromosome 8 gamma satellite sequences were used as flanking DNA in mouse cells. Until recently, no chromatin insulator sequences were known to completely prevent gene silencing on a long term basis in transfected cells. The human gamma-satellite sequences demonstrate a higher efficiency than any known chromatin insulator identified so far in intergenic regions, and may have invaluable applications in the fields of gene therapy, protein expression, and cellular reprogramming where adequate expression of the transgene is essential for long term therapeutic or developmental success.

Further R&D Needed:  erythroleukemia

• Analysis of insulator activity of gamma-satellite DNA in human and mouse hematopoetic cells
• No other additional experimental is needed. The following is optional
• It is also possible to combine gamma-satellite insulator with new construction of Human Artificial Chromosome (HAC) recently constructed by the inventors. It may result in development of a novel gene expression system for gene therapy based on autonomously replicating HAC with a regulated centromere carrying gamma-satellite insulators.

R&D Status:
Pre-clinical in vitro validation (mouse hematopoetic erythroleukemia cells)

IP Status:

• U.S. Provisional Application No. 60/890,176 filed 15 Feb. 2007
• PCT Application No. PCT/US2008/054170 filed 15 Feb. 2008

Value Proposition:

• Ability to prevent gene silencing and to allow for long term expression of transgenes
• Ability to improve the efficacy of gene therapy, protein expression, and cellular reprogramming techniques

Contact Information:
John D. Hewes, Ph.D.
NCI Technology Transfer Center
Phone: 301-435-3121
E-mail: Hewesj@mail.nih.gov

Reference:  #681 LF

Posted 07/16/2008